BOSTON - Deloitte & Touche LLP said on Monday it hired a former senior FBI official as its new director of security and privacy, as the firm seeks to help its client companies fight the threat from increasingly sophisticated computer hackers.

Mary E. Galligan, who supervised the FBI's investigation into the 11 September attacks during a more than 25 year career in law enforcement, will advise Fortune 500 companies on cyber security risks for Deloitte.

She began her role last week, Deloitte said.

Galligan joined the FBI in 1988 and most recently served as special agent in charge of the FBI New York Office's special operations and cyber division.

Deloitte is one of the world's biggest consulting firms that advises companies on cyber security and privacy issues.